Abstract
Within the framework of the physical forcing, we describe and quantify the key ecosystem components and basic food
web structure of the Barents Sea. Emphasis is given to the energy flow through the ecosystem from an end-to-end perspective,
i.e. from bacteria, through phytoplankton and zooplankton to fish, mammals and birds. Primary production in the
Barents is on average 93 g C m 2 y 1, but interannually highly variable (±19%), responding to climate variability and
change (e.g. variations in Atlantic Water inflow, the position of the ice edge and low-pressure pathways). The traditional
focus upon large phytoplankton cells in polar regions seems less adequate in the Barents, as the cell carbon in the pelagic is
most often dominated by small cells that are entangled in an efficient microbial loop that appears to be well coupled to the
grazing food web. Primary production in the ice-covered waters of the Barents is clearly dominated by planktonic algae
and the supply of ice biota by local production or advection is small. The pelagic–benthic coupling is strong, in particular
in the marginal ice zone. In total 80% of the harvestable production is channelled through the deep-water communities and
benthos. 19% of the harvestable production is grazed by the dominating copepods Calanus finmarchicus and C. glacialis in
Atlantic or Arctic Water, respectively. These two species, in addition to capelin (Mallotus villosus) and herring (Clupea
harengus), are the keystone organisms in the Barents that create the basis for the rich assemblage of higher trophic level
organisms, facilitating one of the worlds largest fisheries (capelin, cod, shrimps, seals and whales). Less than 1% of the
harvestable production is channelled through the most dominating higher trophic levels such as cod, harp seals, minke
whales and sea birds. Atlantic cod, seals, whales, birds and man compete for harvestable energy with similar shares. Climate
variability and change, differences in recruitment, variable resource availability, harvesting restrictions and management
schemes will influence the resource exploitation between these competitors, that basically depend upon the efficient
energy transfer from primary production to highly successful, lipid-rich zooplankton and pelagic fishes.
2006 Elsevier Ltd. All rights reserved.
web structure of the Barents Sea. Emphasis is given to the energy flow through the ecosystem from an end-to-end perspective,
i.e. from bacteria, through phytoplankton and zooplankton to fish, mammals and birds. Primary production in the
Barents is on average 93 g C m 2 y 1, but interannually highly variable (±19%), responding to climate variability and
change (e.g. variations in Atlantic Water inflow, the position of the ice edge and low-pressure pathways). The traditional
focus upon large phytoplankton cells in polar regions seems less adequate in the Barents, as the cell carbon in the pelagic is
most often dominated by small cells that are entangled in an efficient microbial loop that appears to be well coupled to the
grazing food web. Primary production in the ice-covered waters of the Barents is clearly dominated by planktonic algae
and the supply of ice biota by local production or advection is small. The pelagic–benthic coupling is strong, in particular
in the marginal ice zone. In total 80% of the harvestable production is channelled through the deep-water communities and
benthos. 19% of the harvestable production is grazed by the dominating copepods Calanus finmarchicus and C. glacialis in
Atlantic or Arctic Water, respectively. These two species, in addition to capelin (Mallotus villosus) and herring (Clupea
harengus), are the keystone organisms in the Barents that create the basis for the rich assemblage of higher trophic level
organisms, facilitating one of the worlds largest fisheries (capelin, cod, shrimps, seals and whales). Less than 1% of the
harvestable production is channelled through the most dominating higher trophic levels such as cod, harp seals, minke
whales and sea birds. Atlantic cod, seals, whales, birds and man compete for harvestable energy with similar shares. Climate
variability and change, differences in recruitment, variable resource availability, harvesting restrictions and management
schemes will influence the resource exploitation between these competitors, that basically depend upon the efficient
energy transfer from primary production to highly successful, lipid-rich zooplankton and pelagic fishes.
2006 Elsevier Ltd. All rights reserved.